This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Motor vehicle crashes are the leading cause of death and morbidity to children. While the mechanical properties of the adult cervical spine and cranium have been extensively published, there is a paucity of data characterizing the properties of the pediatric spine and skull. This data is critical for the development of improved design and performance criteria for child anthropomorphic test devices (crash test dummies), and to better understand the biomechanical basis of head and neck injury in children. The purpose of the present study is to provide the constitutive properties of the pediatric neurocentral synchondrosis. The neurocentral synchondrosis is a cartilaginous growth region between the vertebral body and the neural arch that typically ossifies between 6 and 8 years of age. Synchondrosis segments are harvested from a pediatric post-mortem human subject (PMHS) and subjected to a battery of tests including;preconditioning, quasi-static fixed-fixed force displacement, stress relaxation and constant velocity tests. Inverse finite element analysis (FEA) is used to determine the constitutive properties of subject specific pediatric synchondrosis tissues. Micro Computed Tomography scans (Micro CT) of vertebrae are used to render 3D surfaces in the Amira 5.0 software package (TGS, Inc.). These surfaces are imported into Hypermesh 7.0 (Altair Engineering), where a solid mesh of the neurocentral synchondrotic joint is generated. The constitutive properties of the model are optimized (LS-Opt) with the objective to replicate force-displacement behavior from laboratory testing. SPECIMEN PREPARATION: Specimens will be prepared by Injury and Orthopaedic Biomechanics Research laboratory staff, including: Jason Luck and Brian Arnold. Specimens will be placed into a glass vial suitable for placement in the imaging fixture. We discussed with both Dr. Johnson and Badea that we would need to come in initially and do a final check on the exact size constraints that we will be working with in the imaging fixture. From that point we will fix our specimens into a container that will be suitable for the imaging fixture. In the past we used a small glass vial, but since that time I believe there may have been some changes to the imaging fixture Our protocol will be to place the specimens into a small glass vial with a cap that will fit appropriately into the imaging fixture. The specimen/tissue will be placed into a glass vial and protocol will be followed to ensure that the outside of the glass vial is considered "clean.".